<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2015, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (http://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
 * @license    http://opensource.org/licenses/MIT    MIT License
 * @link    http://codeigniter.com
 * @since    Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter Driver Library Class
 *
 * This class enables you to create "Driver" libraries that add runtime ability
 * to extend the capabilities of a class via additional driver objects
 *
 * @package        CodeIgniter
 * @subpackage    Libraries
 * @category    Libraries
 * @author        EllisLab Dev Team
 * @link
 */
class CI_Driver_Library {

    /**
     * Array of drivers that are available to use with the driver class
     *
     * @var array
     */
    protected $valid_drivers = array();

    /**
     * Name of the current class - usually the driver class
     *
     * @var string
     */
    protected $lib_name;

    /**
     * Get magic method
     *
     * The first time a child is used it won't exist, so we instantiate it
     * subsequents calls will go straight to the proper child.
     *
     * @param    string    Child class name
     * @return    object    Child class
     */
    public function __get($child)
    {
        // Try to load the driver
        return $this->load_driver($child);
    }

    /**
     * Load driver
     *
     * Separate load_driver call to support explicit driver load by library or user
     *
     * @param    string    Driver name (w/o parent prefix)
     * @return    object    Child class
     */
    public function load_driver($child)
    {
        // Get CodeIgniter instance and subclass prefix
        $prefix = config_item('subclass_prefix');

        if ( ! isset($this->lib_name))
        {
            // Get library name without any prefix
            $this->lib_name = str_replace(array('CI_', $prefix), '', get_class($this));
        }

        // The child will be prefixed with the parent lib
        $child_name = $this->lib_name.'_'.$child;

        // See if requested child is a valid driver
        if ( ! in_array($child, $this->valid_drivers))
        {
            // The requested driver isn't valid!
            $msg = 'Invalid driver requested: '.$child_name;
            log_message('error', $msg);
            show_error($msg);
        }

        // Get package paths and filename case variations to search
        $CI = get_instance();
        $paths = $CI->load->get_package_paths(TRUE);

        // Is there an extension?
        $class_name = $prefix.$child_name;
        $found = class_exists($class_name, FALSE);
        if ( ! $found)
        {
            // Check for subclass file
            foreach ($paths as $path)
            {
                // Does the file exist?
                $file = $path.'libraries/'.$this->lib_name.'/drivers/'.$prefix.$child_name.'.php';
                if (file_exists($file))
                {
                    // Yes - require base class from BASEPATH
                    $basepath = BASEPATH.'libraries/'.$this->lib_name.'/drivers/'.$child_name.'.php';
                    if ( ! file_exists($basepath))
                    {
                        $msg = 'Unable to load the requested class: CI_'.$child_name;
                        log_message('error', $msg);
                        show_error($msg);
                    }

                    // Include both sources and mark found
                    include_once($basepath);
                    include_once($file);
                    $found = TRUE;
                    break;
                }
            }
        }

        // Do we need to search for the class?
        if ( ! $found)
        {
            // Use standard class name
            $class_name = 'CI_'.$child_name;
            if ( ! class_exists($class_name, FALSE))
            {
                // Check package paths
                foreach ($paths as $path)
                {
                    // Does the file exist?
                    $file = $path.'libraries/'.$this->lib_name.'/drivers/'.$child_name.'.php';
                    if (file_exists($file))
                    {
                        // Include source
                        include_once($file);
                        break;
                    }
                }
            }
        }

        // Did we finally find the class?
        if ( ! class_exists($class_name, FALSE))
        {
            if (class_exists($child_name, FALSE))
            {
                $class_name = $child_name;
            }
            else
            {
                $msg = 'Unable to load the requested driver: '.$class_name;
                log_message('error', $msg);
                show_error($msg);
            }
        }

        // Instantiate, decorate and add child
        $obj = new $class_name();
        $obj->decorate($this);
        $this->$child = $obj;
        return $this->$child;
    }

}

// --------------------------------------------------------------------------

/**
 * CodeIgniter Driver Class
 *
 * This class enables you to create drivers for a Library based on the Driver Library.
 * It handles the drivers' access to the parent library
 *
 * @package        CodeIgniter
 * @subpackage    Libraries
 * @category    Libraries
 * @author        EllisLab Dev Team
 * @link
 */
class CI_Driver {

    /**
     * Instance of the parent class
     *
     * @var object
     */
    protected $_parent;

    /**
     * List of methods in the parent class
     *
     * @var array
     */
    protected $_methods = array();

    /**
     * List of properties in the parent class
     *
     * @var array
     */
    protected $_properties = array();

    /**
     * Array of methods and properties for the parent class(es)
     *
     * @static
     * @var    array
     */
    protected static $_reflections = array();

    /**
     * Decorate
     *
     * Decorates the child with the parent driver lib's methods and properties
     *
     * @param    object
     * @return    void
     */
    public function decorate($parent)
    {
        $this->_parent = $parent;

        // Lock down attributes to what is defined in the class
        // and speed up references in magic methods

        $class_name = get_class($parent);

        if ( ! isset(self::$_reflections[$class_name]))
        {
            $r = new ReflectionObject($parent);

            foreach ($r->getMethods() as $method)
            {
                if ($method->isPublic())
                {
                    $this->_methods[] = $method->getName();
                }
            }

            foreach ($r->getProperties() as $prop)
            {
                if ($prop->isPublic())
                {
                    $this->_properties[] = $prop->getName();
                }
            }

            self::$_reflections[$class_name] = array($this->_methods, $this->_properties);
        }
        else
        {
            list($this->_methods, $this->_properties) = self::$_reflections[$class_name];
        }
    }

    // --------------------------------------------------------------------

    /**
     * __call magic method
     *
     * Handles access to the parent driver library's methods
     *
     * @param    string
     * @param    array
     * @return    mixed
     */
    public function __call($method, $args = array())
    {
        if (in_array($method, $this->_methods))
        {
            return call_user_func_array(array($this->_parent, $method), $args);
        }

        throw new BadMethodCallException('No such method: '.$method.'()');
    }

    // --------------------------------------------------------------------

    /**
     * __get magic method
     *
     * Handles reading of the parent driver library's properties
     *
     * @param    string
     * @return    mixed
     */
    public function __get($var)
    {
        if (in_array($var, $this->_properties))
        {
            return $this->_parent->$var;
        }
    }

    // --------------------------------------------------------------------

    /**
     * __set magic method
     *
     * Handles writing to the parent driver library's properties
     *
     * @param    string
     * @param    array
     * @return    mixed
     */
    public function __set($var, $val)
    {
        if (in_array($var, $this->_properties))
        {
            $this->_parent->$var = $val;
        }
    }

}
